|Livestock Research for Rural Development|
Most families in Cambodia raise chickens and even a very poor family will have at least 5-6 local hens and a cockerel that scavenge around their households. It is a common belief that the local breeds of chicken are very efficient in scavenging and searching for feed which helps to reduce the expenditure on supplements. Nevertheless, little is known at farmer level about interventions which could improve productivity.
The aims of this study were:
Growing chickens (30 local and 30 exotic; about 500 g initial weight) were managed under (i) total confinement, (ii) scavenging on pasture or (iii) scavenging in an integrated farm area with fruit trees, a biodigester and duckweed ponds ("biomass" treatment). Birds on the scavenging treatments were confined at night time when they had free access to both broken rice and ground soya beans. The experiment lasted 70 days during the rainy season, starting at the end of July and finishing in the middle of October 1997.
Only 9 of the 30 exotic chickens survived until the end of the 70 day experiment compared with 24 out of 30 for the local breed. Autopsy analysis indicated that Newcastle disease was the main cause of the mortality.
The intake of broken rice was similar for the chickens in both scavenging treatments (40-50 g/day) but there were significant differences in intakes of ground soya beans (Figure 1). Birds scavenging in the integrated farm area consumed on average 8 g/day of soya beans (2.7 g protein) while those scavenging on pasture consumed an average of 16 g/day (5.44 g protein). There was considerable variation in daily intakes of soya bean during the course of the experiment with increasing intake with time for the pasture group compared with an increase from 14 to 56 days followed by a decline for the "biomass" group.
Growth data are presented only for the local chickens as in two of the management systems there were no survivors in the exotic birds. There were significant differences (P=0.001) in mean liveweights of the local chickens at all stages of the trial with the two scavenging treatments being superior to the confinement treatment at all intervals from 14 days onwards (Figure 2). Final liveweights of local chickens in the two scavenging treatments were 1390 g on pasture and 1478 g in the biomass group (SE of means ±84) compared with 667 g for the confinement group.
The opportunity to scavenge is a way of allowing the chickens to correct any nutritional deficiency in the feeds offered as supplements. These supplements were broken rice and ground whole soya beans which together would provide adequate energy, protein and essential fatty acids. However, both feeds are low in minerals and vitamins and it is possible that deficiencies in these nutrients were the reasons for the poor growth of the confined chickens.
|Figure 1: Intakes of ground soya beans by local chickens scavenging on pasture or in an integrated farm area (biomass)||Figure 2: Mean live weights of local chickens scavenging
on pasture, or in integrated farm area (biomass), and in confinement
Under the conditions of this experiment, the local breed of chicken was more resistant to disease than exotic chickens, even though birds of both breeds had been vaccinated against the common local diseases, including Newcastle, before the experiment started. The nature of the area available for scavenging influenced strongly the feed intake pattern of the chickens when these had free access to both energy- and protein-rich supplements. Chickens with access to an integrated farm area with fruit trees, a biodigester and duckweed ponds, ate significantly less ground soya bean than when the scavenging area was exclusively pasture.
It is recommended that for poor farmers:
Research is needed to identify:
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